Playing it safe

Researchers in the Faculty of Engineering have devised a playground safety standard instrument that aims to make children's playgrounds safer, thereby reducing the frequency and severity of injuries.

Dr David Eager and Chris Chapman have designed a portable rig to test playground undersurfaces. From a predetermined height, the rig drops a headform made of magnesium alloy onto a playground surface and measures its impact. Chapman's software program records the measurements and provides a Head Injury Criteria (HIC) value.

"The standards for the headform came from automotive testing, essentially it is the same head used on a crash-test dummy," Chapman says.

The headform, connected to three accelerometers, measures acceleration during impact, enabling Dr Eager to measure the impact-absorbing properties of the playground undersurfacing material. The headform is dropped onto the surface from increased heights until the surface fails the test. To fail, the test total acceleration has to be over 200g (g is an equivalent acceleration to one gravitational force at sea level) and HIC over 1000.

Dr Eager and Chapman intend making the rig more portable, with work under way to remove the laptop attached to the equipment. Engineering undergraduate Alex Green has completed a capstone project that focused on creating electronics to fit inside the headform. These record details currently transmitted via cables attached to the head.

The researchers are testing surfaces such as bark, sand, PVA and LDPE foam, and shredded recycled car tyres with a wear layer of EPDM granules. "Most man-made surfaces can be poured like concrete to the desired thickness, because the greater the height of any playground equipment the greater the thickness the surface needs to be" Chapman says.

The current Australian playground safety standard stipulates a maximum free height fall of 2.5 metres onto an appropriate undersurface. The standard also stipulates that the force with which a child hits the undersurface should not exceed 1000 HIC. "This means that playground undersurfacing systems have to correlate with the possible free height of fall from the equipment in the fall zone," Dr Eager says.

"In Australia approximately 40,000 injuries a year can be attributed to accidents that occur in children's playgrounds. This is partly due to undersurfacing failing to comply with the safety standard."

The first part of Dr Eager's new six-part standard focuses on general playground requirements and the remaining five are dedicated to specific types of equipment. One of the most important changes achieved is the introduction of minimum space around equipment. "This encompasses three types of space — equipment space, free space and falling space," Dr Eager says.

"As far as we are aware we are the only ones in NSW with a portable test rig that fully conforms to the current safety standard," says Chapman. "There are about 1000 childcare centres in Sydney and approximately 2000 other childcare playgrounds around the State, all of which have to be tested.

"We hope to build more rigs including one for Kidsafe NSW so they can conduct testing in childcare centres in socio-economically disadvantaged areas. We will provide the rig, training and software so they can test playground surfaces themselves. This is of considerable value to the Department of Community Services NSW as playground undersurfacing must be tested for compliance every three years and each test costs approximately $500."

"Playgrounds often provide children's main opportunity for physical exercise," says Dr Eager. "Areas of natural environment and activities such as bike riding are often not available for children living in an overcrowded and often dangerous urban environment."

Children are natural risk takers, they are curious and prone to climbing and jumping, which leads inevitably to accidents. "Given the curious nature of children, we can't make playgrounds completely safe, so it's all about risk management," he says.

"Risk management within the playground environment is more complex than industrial safety because the primary aim of a playground is to stimulate a child's imagination, provide excitement and adventure and allow scope for children to develop their own ideas of play.

"Ideally playgrounds should encourage the development of motor skills and present the child with manageable challenges. A playground should also include elements that encourage the development of a child's creative, cognitive, social and sensual skills. Risk taking should be taken as a given with child development. A well-designed playground encourages the child to take risks, but in a semi-controlled environment that protects a child from hazards he or she may be unable to foresee when using playground equipment.

"A well-designed playground will help the child develop a sense of boundaries, an important and often overlooked life skill."

Dr Eager is a member of the Australian Standards Committee, the ASTM International Standards Committee for Children's Playgrounds and also serves on the board of Kidsafe NSW.